Brake Warning Light

[68 P.O.S.]

Mine turned on after work today. I haven't had time to check it very well yet, but I did find a burned out tail light. I had a co-worker follow me home just in case, but the brakes worked fine with no noticeable difference from normal performance. What does this light exactly warn you of??? Is it for anything specific or is it for the overall braking system as a whole? My brakes, hoses, and cylinders are all <1 yr old so I doubt it is that. Will I need a new prop vale maybe? This may be the perfect excuse to upgrade to power discs! Hopefully my wife will see it that way.

[71swb4x4]

The wire for the light goes to the master cylinder, so I would guess it's telling you the brake fluid is low.

[northerngmc]

Normally it is hooked up to the master cylinder, so check the fluid and look for leaks.

HAve you owned the truck very long? I have read on here where some have installed a switch on the E brake pedal and hooked it up to light up when the E brake is on.

[69halfton]

just recently, everytime i start the truck, the brake light comes on, but then goes off after maybe 2-3 seconds.

seems normal like every other car these days, except that it just started doing it for no reason...?

[68 P.O.S.]

I checked the fluid level and it was fine. After I read your post 71swb4x4, I realized that I checked the level before driving home. So, I just double checked it to be sure and realized I did something really stupid. After I initially checked the fluid level, one of my superiors distracted me trying to help, and I forgot to put the cap back on the reservoir. Luckily I didn't lose the cap. After it fell off and got fluid everywhere, it wedged between the speedo cable & frame. I think that qualifies for the dumbass of the month award that someone was talking about on here. on a good note, the fluid level is still fine by the way. So does anyone have any other suggestions????

[68 P.O.S.]

Originally Posted by northerngmc

Have you owned the truck very long? I have read on here where some have installed a switch on the E brake pedal and hooked it up to light up when the E brake is on.

I've had the truck for 2 yrs now. I installed a painless harness and have had no problems with it except for my own stupid mistakes I've had to fix. I don't know why, but if anyone has problems with their truck, it is always me. My friends always mess with me about that. Anyway, I don't have an e brake on it, I haven't splurged for that yet.

[Longhorn Man]

The red brake light is supposed to come on when you start the truck... it's supposed to be on when the key is in the crank position.
otherwise, all it will indicate, is an unballanced pressure in the system.
it won't show if you are low, but it will tell you if one side is empty.

I would start with unplugging the brown wire from the proportioning valve. If the light turns off, then it is doing it's job properly, and there is actually a problem being indicated.
if it stays on, troubleshoot your harness you installed.
After that, i would bleed the whole system very thouroughly... keeping a very close eye for leaks.
if it is still on, then you need to reset the valve inside the proportioning valve assembly. Do this by slamming on the brakes as fast and hard as you can (truck not moving)... imagine running 110 MPH, and a cow jumps in front of you.
yeah, THAT hard.

[68 P.O.S.]

Originally Posted by Longhorn Man

I would start with unplugging the brown wire from the proportioning valve. If the light turns off, then it is doing it's job properly, and there is actually a problem being indicated.
if it stays on, troubleshoot your harness you installed.
After that, i would bleed the whole system very thouroughly... keeping a very close eye for leaks.
if it is still on, then you need to reset the valve inside the proportioning valve assembly. Do this by slamming on the brakes as fast and hard as you can (truck not moving)... imagine running 110 MPH, and a cow jumps in front of you.
yeah, THAT hard.

I unplugged the brown wire and the light stays on. Fluid level is still okay. Tried resetting the valve to no avail. I'll have to trace the system and harness tomorrow in the sunlight. Any idea which section of my Painless harness I should check? If it's not either of those things is the prop valve then?

[Longhorn Man]

if you unplug it, and the light stays on, then the problem si probably in the harness.
I have no clue where to look in your harness. I have never messed with an aftermarket harness. I've only seen one truck in my life that NEEDED a replacement harness.